[dradernh]

The battery that came in my F22 M240i is rated at 92AH, and the BMW dealers' replacement batteries I see online are rated at 80AH. What's the practical difference between those ampere-hour ratings for an owner?

[John in VA]

https://f30.bimmerpost.com/forums/sh....php?t=1544177

https://f15.bimmerpost.com/forums/sh....php?t=1754369

[dradernh]

Originally Posted by John in VA

https://f30.bimmerpost.com/forums/sh....php?t=1544177

https://f15.bimmerpost.com/forums/sh....php?t=1754369

Thanks. I'd come across that general information via searches.

I guess what I'm wondering is if the dealer were to replace my 92AH battery with an 80AH battery, what difference is it going to make to me, if any?

[Kernel Kurtz]

Either should work fine so long as it is registered to the car appropriately. That said these cars work their batteries pretty hard and I personally would not opt for a smaller capacity battery.

[dradernh]

Originally Posted by Kernel Kurtz

Either should work fine so long as it is registered to the car appropriately. That said these cars work their batteries pretty hard and I personally would not opt for a smaller capacity battery.

If I have the dealer change the battery, and there's a choice, I'll certainly opt for the higher-amperage battery.

[Shovelman]

It depends on how hard you use your battery. Short drives may not let your battery fully recharge. Auto restart may run it down. Seat and steering wheel heaters suck some power. Sitting in the car with the radio on and the engine off, aftermarket lighting, audio systems, convertible top, etc.

Presumably the 80 AH is lighter, as well as cheaper.

[bensanford]

I was thinking about proactively replacing the AGM original battery in my 230i. The battery is approaching 7 years but seems fine. I was looking at the battery in the floor of the trunk and it is certainly a lot cleaner that batteries in my previous cars which were usually in the hot engine compartment. (maybe that's why it is lasting longer?)

The battery in my 230i appears to be Group size 49 (or DIN size H8). It's almost 14" long, and rated at 90 Ah. Then I looked in my wife's 330, and the battery installed in it is considerably smaller, Group 49 (or DIN size H5), and it's considerably smaller, being just under 10" in length, and rated at 70 Ah. There is plenty of room in the 330 for the larger battery, and there are already threaded mounting holds in the floor of the trunk to accommodate a larger battery - but of course that one doesn't need replacement yet.

For now, I just need to find the right H8 sized battery for by 230i, and fortunately I have time to figure that out. I think I will stay with the largest size, which won't add that much weight.

[John in VA]

Originally Posted by bensanford

For now, I just need to find the right H8 sized battery for by 230i, and fortunately I have time to figure that out. I think I will stay with the largest size, which won't add that much weight.

Shop Costco for the AGM H8 from Interstate. H8 is the size.

[dradernh]

Originally Posted by John in VA

Shop Costco for the AGM H8 from Interstate. H8 is the size.

Granted, I'm a total novice at this, but when I go to Costco and tell it which car I have, it returns a single 80aH battery: https://costco.interstatebatteries.c...827&Country=US.

The price is certainly attractive.

[Rocky58]

If you don’t change the battery specs you don’t have to code it but you do have to register it so that it knows it is a new battery and doesn’t overcharge it. If you buy a battery with a significantly different Ah, you have to code it. If you buy your own battery, you will have to do this yourself or take it to a shop that can and will do it as the chain shops don’t have the equipment to do that. I have not done this myself but you can do it I believe with a scanner and Carly or similar software. Consumer Reports rates the AC Delco H8 the best and they do charge discharge them till they fail. It’s like 190 bucks at Walmart. This is what I plan to replace mine with. Has anyone done this with Carly?

[freakystyly]

Thanks for the battery reminder, I will need to do mine this year too. Been getting the discharge warning with colder temps last winter.

My Costco has Energizer H8 AGM 95ah batteries for $324, got to love the "Canada" tax. I think the dealer quoted me a similar price but I'm not sure of what their specs were.

[bensanford]

Originally Posted by dradernh

Granted, I'm a total novice at this, but when I go to Costco and tell it which car I have, it returns a single 80aH battery: https://costco.interstatebatteries.c...827&Country=US.

The price is certainly attractive.

I was at my local Costco, and the battery you identified is indeed the only one close to the original size that they appear to stock. This is the DIN size H7, or the Group size 94R. It is an 80 Ah battery. It is smaller had has less capacity than the DIN size H8 original battery in my 230i (rated at 90 Ah), but larger than the original battery in my wife's 330i (rated at 70 Ah).

In either case it would be necessary to both do coding for the new battery size and also do the registration for the new battery.

[John in VA]

Originally Posted by dradernh

Granted, I'm a total novice at this, but when I go to Costco and tell it which car I have, it returns a single 80aH battery:
https://costco.interstatebatteries.c...827&Country=US.

The price is certainly attractive.

Costco can be sticklers on tires & batteries, requiring what came on the car originally. Tell them you have a 2003 530i - it takes the H8. H7 & H8 are very similar in size - H8 is ~one inch longer. Either will do the job for you.

https://costco.interstatebatteries.c...691&Country=US